1.1 The purpose of an interlaboratory study is to determine the variability in results caused by differences among laboratories following a prescribed test method, the consistency from material to material of this variability, and the type of additional standardization needed, if any. The study may be made to obtain information for improving the test method or to arrive at an estimate of the precision of an existing method for publication. It may also include a comparison of alternative test methods.

1.2 To achieve the objectives in 1.1 satisfactorily, it is essential that a sound statistical design be employed in the planning of an interlaboratory study. This practice gives the basic principles involved in the planning in order to make the data amenable to statistical analysis and interpretation.

1.3 This practice has been written for the task group chairman responsible for the preparation or the revision of a standard test method. It tells him what information he needs in order to properly plan an interlaboratory study (Sections 1 through 10), it outlines the procedure for conducting the study (Section 11), and it gives him background information for understanding the analysis (Section 12) and interpretation (Sections 13 through 15) of the results.

1.4 While the services of a statistician are not absolutely necessary for the design, analysis, and interpretation of interlaboratory studies, questions often arise that could be readily answered by a statistician familiar with the analysis used herein. Hence, the task group chairman should arrange whenever possible to consult with a statistician both during the planning and during the analysis and interpretation.

1.5 This practice is similar to TAPPI T1200, which details the analysis using a set of typical data.

1.6 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.